The first anniversary of the September 11 attacks in the United States, which left more than 3,000 people dead, is being marked around the world.

The BBC is covering many of the planned events on television, radio and online, as well as hosting discussion programmes and forums.

In New York:

1200 GMT/0800 local time: Memorial service at the World Trade Center site starts.

1246 GMT/0846 local: A moment's silence marks the time when the first hijacked airliner struck one of the Twin Towers. Former city Mayor Rudolph Giuliani leads the reading of the names of those who died at the World Trade Center.

1429 GMT/1029 local: The ceremony concludes the moment the second of the twin towers collapsed. Churches throughout the city toll their bells, and victims' families are invited to descend a specially-built ramp to the lowest point of the World Trade Center site.

1500 GMT/1100 local: A special service is held at Wall Street's Trinity Church.

President Bush said the world changed on that day

1800 GMT/1400 local: The United Nations holds a solemn ceremony of remembrance.

2140 GMT/1740 local: President George W Bush lays a wreath at the World Trade Center site.

0201 GMT 12 September/2201 local: Leaders from around the world join a ceremony at The Sphere, a sculpture from the World Trade Center that is now part of a temporary memorial in Battery Park. An eternal flame is lit.
Candlelight gatherings take place across New York throughout the evening.

1235 GMT/0835 local: A ceremony on the White House lawn begins, leading up to a moment of silence at 1246 GMT/0846 local.

1330 GMT/0930 local: Ceremony at the Pentagon starts.

1337 GMT/0937 local: A moment's silence is observed at the time a hijacked plane hit the Pentagon building.

1400 GMT/1000 local: President Bush speaks at the ceremony.

In Somerset County, Pennsylvania:

1645 GMT/1245 local: President Bush lays a wreath in Shanksville, where one of the hijacked planes went down. A moment's silence is held.

In Kabul, Afghanistan:

0200 GMT/0630 local: Sunrise service held at Bagram, the main US airbase in Afghanistan. Anniversary commemorations are held at the base from 1200GMT/1830.

In London, UK

0900 GMT/1000 local:
A remembrance ceremony is held outside the US Embassy, addressed by Ambassador William Farish. A Union Flag found at Ground Zero is to be presented.

1215GMT/1315 local:
Commemorative service at St Paul's cathedral attended by royalty, senior politicians and diplomats, as well as representatives of the families of UK victims, the US community in the UK, emergency services and the business community. More than 3,000 petals to be released representing all those who died.

1000 GMT/1200 local: A memorial ceremony is held at the Berlin Dome, attended by Chancellor Gerhard Schroeder and President Johannes Rau.

In Paris, France:

1000 GMT/1200 local: President Jacques Chirac visits US Embassy for a minute's silence.

The BBC will also mark the anniversary on 11 September with a number of discussions and forums:

1130 GMT/1230 local: , America and the Muslim World, a live discussion on World television. Guests will be American broadcaster Bonnie Greer and a member of the Muslim Council of Britain.

1510 GMT/1610 local: Your reflections, on World Television. Peter Gould presents a live forum from New York with some of the survivors of the attack.

1530 GMT/1630 local: Changed Lives - Discussion on World television and News 24 about the psychological effects of the terrorist attacks. Guests include Susan Frederick, who was inside the World Trade Center on 11 September, and Dr Michael Isaac from the Institute of Psychiatry.

1700 GMT/1800 local: Six O'clock News on BBC1 includes a forum live from New York with Richard Wadja, a survivor of the Twin Towers attacks.

1830 GMT/1930 local: America's Place in the World - discussion on World television and News 24. Guests are Steven Simon, director of the International Institute for Strategic Studies in London, and Dr Iftikhar Malik, academic and author of several books on Islam and the West.

1830 GMT/1930 local: Business: Reaction and Recovery - live debate on World television. Discussing the economic effects of September 11 will be Will Hutton, author of the book The World We're In, and BBC North America Business Correspondent Patrick O'Connell.